scholarly journals Cochlea sparing optimized radiotherapy for nasopharyngeal carcinoma

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Enkelejda Lamaj ◽  
Erwin Vu ◽  
Janita E. van Timmeren ◽  
Chiara Leonardi ◽  
Louise Marc ◽  
...  
Keyword(s):  
At Risk ◽  
Nasopharyngeal Carcinoma ◽  
Organs At Risk ◽  
Standard Of Care ◽  
Target Volume ◽  
Quality Parameters ◽  
Rank Test ◽  
Conformity Index ◽  
Platinum Based Chemotherapy ◽  
Signed Rank Test

Abstract Background Definitive chemoradiotherapy (CRT) is standard of care for nasopharyngeal carcinoma. Due to the tumor localization and concomitant platinum-based chemotherapy, hearing impairment is a frequent complication, without defined dose-threshold. In this study, we aimed to achieve the maximum possible cochleae sparing. Materials and methods Treatment plans of 20 patients, treated with CRT (6 IMRT and 14 VMAT) based on the QUANTEC organs-at-risk constraints were investigated. The cochleae were re-delineated independently by two radiation oncologists, whereas target volumes and other organs at risk (OARs) were not changed. The initial plans, aiming to a mean cochlea dose < 45 Gy, were re-optimized with VMAT, using 2–2.5 arcs without compromising the dose coverage of the target volume. Mean cochlea dose, PTV coverage, Homogeneity Index, Conformity Index and dose to other OAR were compared to the reference plans. Wilcoxon signed-rank test was used to evaluate differences, a p value < 0.05 was considered significant. Results The re-optimized plans achieved a statistically significant lower dose for both cochleae (median dose for left and right 14.97 Gy and 18.47 Gy vs. 24.09 Gy and 26.05 Gy respectively, p < 0.001) compared to the reference plans, without compromising other plan quality parameters. The median NTCP for tinnitus of the most exposed sites was 11.3% (range 3.52–91.1%) for the original plans, compared to 4.60% (range 1.46–90.1%) for the re-optimized plans (p < 0.001). For hearing loss, the median NTCP of the most exposed sites could be improved from 0.03% (range 0–99.0%) to 0.00% (range 0–98.5%, p < 0.001). Conclusions A significantly improved cochlea sparing beyond current QUANTEC constraints is feasible without compromising the PTV dose coverage in nasopharyngeal carcinoma patients treated with VMAT. As there appears to be no threshold for hearing toxicity after CRT, this should be considered for future treatment planning.

scholarly journals Automatic Planning for Nasopharyngeal Carcinoma Based on Progressive Optimization in RayStation Treatment Planning System

2020 ◽  
Vol 19 ◽  
pp. 153303382091571
Author(s):  
Yiwei Yang ◽  
Kainan Shao ◽  
Jie Zhang ◽  
Ming Chen ◽  
Yuanyuan Chen ◽  
...  
Keyword(s):  
At Risk ◽  
Nasopharyngeal Carcinoma ◽  
Organs At Risk ◽  
Planning System ◽  
Treatment Planning System ◽  
Conformity Index ◽  
Homogeneity Index ◽  
Automatic Planning ◽  
The Difference ◽  
Better Than

Objective: To evaluate and quantify the planning performance of automatic planning (AP) with manual planning (MP) for nasopharyngeal carcinoma in the RayStation treatment planning system (TPS). Methods: A progressive and effective design method for AP of nasopharyngeal carcinoma was realized through automated scripts in this study. A total of 30 patients with nasopharyngeal carcinoma with initial treatment was enrolled. The target coverage, conformity index (CI), homogeneity index (HI), organs at risk sparing, and the efficiency of design and execution were compared between automatic and manual volumetric modulated arc therapy (VMAT) plans. Results: The results of the 2 design methods met the clinical dose requirement. The differences in D95 between the 2 groups in PTV1 and PTV2 showed statistical significance, and the MPs are higher than APs, but the difference in absolute dose was only 0.21% and 0.16%. The results showed that the conformity index of planning target volumes (PTV1, PTV2, PTVnd and PGTVnx+rpn [PGTVnx and PGTVrpn]), homogeneity index of PGTVnx+rpn, and HI of PTVnd in APs are better than that in MPs. For organs at risk, the APs are lower than the MPs, and the difference was statistically significant ( P < .05). The manual operation time in APs was 83.21% less than that in MPs, and the computer processing time was 34.22% more. Conclusion: IronPython language designed by RayStation TPS has clinical application value in the design of automatic radiotherapy plan for nasopharyngeal carcinoma. The dose distribution of tumor target and organs at risk in the APs was similar or better than those in the MPs. The time of manual operation in the plan design showed a sharp reduction, thus significantly improving the work efficiency in clinical application.

scholarly journals Comparative study between Acuros XB algorithm and Anisotropic Analytical Algorithm in the case of heterogeneity for the treatment of lung cancer

2018 ◽  
Vol 24 (3) ◽  
pp. 115-119
Author(s):  
Mohammed El Adnani Krabch ◽  
Abdelouahed Chetaine ◽  
Abdelati Nourreddine ◽  
Fatim Zohra Er-Radi ◽  
Laila Baddouh
Keyword(s):  
Lung Cancer ◽  
At Risk ◽  
Heterogeneous Media ◽  
Maximum Dose ◽  
Organs At Risk ◽  
Target Volume ◽  
Conformity Index ◽  
Acuros Xb ◽  
Significant Difference ◽  
The Impact

Abstract The aim of this study was to investigate the impact of heterogeneity on the dose calculation for two algorithms implemented in the TPS “Analytical Anisotropic Algorithm (AAA) and Acuros XB” and validated the use of Acuros XB algorithm in clinical routine. First, we compare the dose calculated by these algorithms and the dose measured at the given point P, which is found after heterogeneity insert. Second, we extend our work on clinical cases that present a complex heterogeneity. By evaluating the impact of the choice of the algorithm on the dose coverage of the tumor, and the dose received by the organs at risk for 20 patients affected by lung cancer. The result of our phantom study showed a good agreement with several studies that showed the superiority of the Acuros XB over the AAA in predicting dose when it concerns heterogeneous media. The treatment plans for 20 lung cancers were calculated by two algorithms AAA and Acuros XB, the results show a statistical significant difference between algorithms for Homogeneity Index and the maximum dose of planning target volume (HI: 0.11±0.01 vs 0.05±0.01 p = 0.04; Dmax: 69.30±3.12 vs 68.51±2.64 p = 0.02). Instead, no statistically significant difference was observed for conformity index CI and mean dose (CI: 0.98±0.18 vs 0.99±0.14 p = 0.33; Dmean: 66.3±0.65 vs 66.10 ±0.61 p = 0.54). For organs at risk, the maximum dose for spinal cord, mean dose and D37 % of lung minus GTV (dose receiving 37% of lung volume) were found to be lower for AAA plans than Acuros XB and the differences were statistically significant (p<0.05). For the heart D33% and D67% were found to be higher for AAA plans than Acuros XB and the differences were statistically significant (p<0.05), but No difference was observed for D100% of the heart. The use of the AXB algorithm is suitable in the case of presence of heterogeneity, because it allows to have a better accuracy close to the Monte Carlo calculation.

scholarly journals Use of a Head-Tilting Baseplate During Tomotherapy to Shorten the Irradiation Time and Protect the Hippocampus and Lens in Hippocampal Sparing-Whole Brain Radiotherapy

2021 ◽  
Vol 20 ◽  
pp. 153303382098682
Author(s):  
Kosei Miura ◽  
Hiromasa Kurosaki ◽  
Nobuko Utsumi ◽  
Hideyuki Sakurai
Keyword(s):  
At Risk ◽  
Planning Target Volume ◽  
Irradiation Time ◽  
Organs At Risk ◽  
Absorbed Dose ◽  
Whole Brain Radiotherapy ◽  
Target Volume ◽  
Whole Brain ◽  
Brain Radiotherapy ◽  
Hippocampal Sparing

Purpose: The aim of this study is to comparatively examine the possibility of reducing the exposure dose to organs at risk, such as the hippocampus and lens, and improving the dose distribution of the planned target volume with and without the use of a head-tilting base plate in hippocampal-sparing whole-brain radiotherapy using tomotherapy. Methods: Five paired images of planned head computed tomography without and with tilt were analyzed. The hippocampus and planning target volume were contoured according to the RTOG 0933 contouring atlas protocol. The hippocampal zone to be avoided was delineated using a 5-mm margin. The prescribed radiation dose was 30 Gy in 10 fractions. The absorbed dose to planning target volume dose, absorbed dose to the organ at risk, and irradiation time were evaluated. The paired t-test was used to analyze the differences between hippocampal-sparing whole-brain radiotherapy with head tilts and without head tilts. Results: Hippocampal-sparing whole-brain radiotherapy with tilt was not superior in planning target volume doses using the homogeneity index than that without tilt; however, it showed better values, and for Dmean and D2%, the values were closer to 30 Gy. Regarding the hippocampus, dose reduction with tilt was significantly greater at Dmax, Dmean, and Dmin, whereas regarding the lens, it was significantly greater at Dmax and Dmin. The irradiation time was also predominantly shorter. Conclusion: In our study, a tilted hippocampal-sparing whole-brain radiotherapy reduced the irradiation time by >10%. Therefore, our study indicated that hippocampal-sparing whole-brain radiotherapy with tomotherapy should be performed with a tilt. The head-tilting technique might be useful during hippocampal-sparing whole-brain radiotherapy. This method could decrease the radiation exposure time, while sparing healthy organs, including the hippocampus and lens.

scholarly journals Dosimetric comparison between 3D conformal and intensity-modulated radiation therapy for prostate cancer

2010 ◽  
Vol 9 (2) ◽  
pp. 77-85 ◽  
Author(s):  
Courtney Buckey ◽  
Gregory Swanson ◽  
Sotirios Stathakis ◽  
Nikos Papanikolaou
Keyword(s):  
Radiation Therapy ◽  
Organs At Risk ◽  
External Beam Radiotherapy ◽  
Radiation Therapy Oncology Group ◽  
Intensity Modulated Radiation Therapy ◽  
Standard Of Care ◽  
Target Volume ◽  
Conformal Radiation Therapy ◽  
Intensity Modulated ◽  
3D Crt

AbstractBackground and Purpose: Intensity-modulated radiation therapy (IMRT) is considered by many to be the standard of care in the delivery of external-beam radiotherapy treatments to the prostate. The purpose of this study is to assess the validity of the purported benefits of IMRT.Materials and Methods: Treatment plans were produced for 10 patients using both 3D conformal radiation therapy (3D-CRT) and IMRT, utilising the dose constraints recommended by the Radiation Therapy Oncology Group (RTOG) 0415 protocol. Three IMRT modalities used in this study were linear accelerator based IMRT, helical tomotherapy, and serial tomotherapy. The prescription to the target, 76 Gy, was the same for all plans.Results: In general the 3D-CRT plans satisfied the RTOG criteria for planning target volume (PTV) coverage, and met or bettered the dose criteria for the organs at risk. PTV coverage was more homogeneous for the IMRT plans than the 3D-CRT plans but not significantly improved.Conclusions: Technically, because the IMRT plans required greater effort for the optimisation, longer treatment times and higher monitor units, the use of IMRT for the fulfilment of the protocol’s dosimetric goals was not justified using these constraints.

scholarly journals Improving indicators of tuberculosis program cascades by leveraging HIV program strategies

2019 ◽  
Vol 9 (4) ◽  
pp. 191-195
Author(s):  
S. C. Meribe ◽  
E. Harausz ◽  
I. Lawal ◽  
A. Ogundeji ◽  
C. Mbanefo ◽  
...  
Keyword(s):  
Standard Of Care ◽  
Rank Test ◽  
Military Hospitals ◽  
Us Army ◽  
Signed Rank ◽  
Before And After ◽  
Army Medical Research ◽  
Signed Rank Test ◽  
The Impact ◽  
Number Of Individuals

Background: To improve rates of human immunodeficiency virus (HIV) case detection and treatment, the Nigerian Ministry of Defense Health Implementation Program and the US Army Medical Research Directorate-Africa/Nigeria introduced a HIV standard of care (SOC) package. Given the integration of tuberculosis (TB) and HIV programs and evolving policies, we evaluated the impact of this strategy on TB program indicators.Methods: Routine, de-identified program data from 27 Nigerian military hospitals were analyzed. Using Wilcoxon signed-rank test, bivariate analyses were performed to compare data from 12 months before and after implementation of the SOC package.Results: Our data showed improvements post-implementation as follows: the number of individuals receiving antiretroviral therapy (ART) screened for TB increased from 14 530 to 29 467 (P < 0.001); the number of individuals with presumptive TB identified increased from 803 to 1800 (P < 0.001); the number of ART clients bacteriologically tested for TB increased from 746 to 1717 (P < 0.001); and the number of ART clients treated for TB increased from 152 to 282 (P < 0.001). Newly registered or relapsed TB cases increased from 436 to 906 (P < 0.001), the number of TB cases with known HIV status increased from 437 to 837 (P < 0.001), the number of TB-HIV co-infected cases increased from 182 to 301 (P = 0.006), and the number of TB-HIV co-infected clients who started ART increased from 101 to 176 (P = 0.003).Conclusion: The implementation of the updated HIV SOC package led to the improvement in key TB diagnosis and treatment indicators. When emulated, this could help improve the performance of other TB programs in countries other than Nigeria.

scholarly journals Shortened Tracer Uptake Time in GA-68-DOTATOC-PET of Meningiomas Does Not Impair Diagnostic Accuracy and PET Volume Definition

Diagnostics ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1084
Author(s):  
Josefine Graef ◽  
Carolin Senger ◽  
Christoph Wetz ◽  
Alexander D. J. Baur ◽  
Anne K. Kluge ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Target Volume ◽  
Tracer Uptake ◽  
Lesion Detection ◽  
Rank Test ◽  
Tracer Injection ◽  
Signed Rank ◽  
Signed Rank Test ◽  
Definition Of ◽  
Time Point

Ga-68-DOTATOC-PET/MRI can affect the planning target volume (PTV) definition of meningiomas before radiosurgery. A shorter tracer uptake time before image acquisition could allow the examination of more patients. The aim of this study was to investigate if shortening uptake time is possible without compromising diagnostic accuracy and PET volume. Fifteen patients (f = 12; mean age 52 years (34–80 years)) with meningiomas were prospectively examined with dynamic [68Ga]Ga-68-labeled [DOTA0-Phe1-Tyr3] octreotide (Ga-68-DOTATOC)-PET/MRI over 70 min before radiosurgery planning. Meningiomas were delineated manually in the PET dataset. PET volumes at each time point were compared to the reference standard 60 min post tracer injection (p.i.) using the Friedman test followed by a Wilcoxon signed-rank test and Bonferroni correction. In all patients, the earliest time point with 100% lesion detection compared to 60 min p.i. was identified. PET volumes did not change significantly from 15 min p.i. (p = 1.0) compared to 60 min p.i. The earliest time point with 100% lesion detection in all patients was 10 min p.i. In patients with meningiomas undergoing Ga-68-DOTATOC-PET, the tracer uptake time can safely be reduced to 15 min p.i. with comparable PET volume and 100% lesion detection compared to 60 min p.i.

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